Panasonic Intellectual Property Management Co., Ltd.

Masato Himeda

Masafumi Yamamoto

Hiroyuki Asano

Takeshi Kamoi

Daisuke Yamahara

Keisuke Seki

Satoru Nagata

Katunobu Hamamoto

Katsuyuki Doi

Hisaya Takikita

Koki Matsui

A DC power supply device includes a rectifier circuit, a conversion circuit and a control circuit. Conversion circuit includes a first capacitor, a first series circuit, a second series circuit, a third series circuit, a second diode and a Zener diode. First series circuit includes a first inductor and a switching element connected in series with each other. Second series circuit includes a second capacitor and a second inductor connected in series with each other. Third series circuit includes a first diode and a third capacitor connected in series with each other. First series circuit is electrically connected between both ends of first capacitor. Second series circuit is electrically connected in parallel with switching element. A cathode of Zener diode is connected with a connection point of first inductor and second capacitor. Zener diode has a Zener voltage larger than an output voltage of conversion circuit.

DC power supply device and lighting system using same

A lighting device includes a rectifier circuit, a conversion circuit, a constant current circuit and a control circuit. The conversion circuit includes a first series circuit, a second series circuit and a third series circuit. The conversion circuit is configured to output a DC current by on/off of a switching element being controlled by the control circuit. A high potential-side terminal of the third capacitor is electrically connected to an output terminal. The low potential-side terminal of the third capacitor is electrically connected to an output terminal, via the constant current circuit.

Lighting device and lighting fixture using same

A lighting device includes: a signal converting circuit which receives a dimming signal that is a rectangular voltage signal, and converts the dimming signal to a DC voltage signal corresponding to a duty ratio of the dimming signal; and a power supply circuit which receives an AC voltage and outputs DC current having a current value corresponding to the DC voltage signal. The signal converting circuit includes a resistor-capacitor (RC) circuit which integrates a signal corresponding to the dimming signal by way of charging and discharging to produce the DC voltage signal, and a time constant of the RC circuit during charging is greater than a time constant of the RC circuit during discharging.

Lighting device and luminaire

A lighting device includes a rectifier circuit, a conversion circuit and a control circuit. A first inductor of a first series circuit and a second inductor of a second series circuit have inductances by which a time period, during which a diode is electrically conducted, is made shorter than a half period of a resonance period of a closed loop circuit. The closed loop circuit includes a first capacitor, the first inductor, a second capacitor and a third capacitor. The control circuit is configured to control a switching element in such a manner that the switching element is turned on at fixed periods.

A lighting device () includes a voltage converter () for generating a predetermined DC voltage, a detector () for obtaining a detection voltage corresponding to a predetermined DC voltage applied across a light source (), a controller () for controlling the voltage converter () so that a current flowing through the light source () is constant, and a determination unit () for determining whether the detection voltage is a preset first reference voltage or higher. The first reference voltage is set higher by a specified voltage than the detection voltage, and is set to vary more slowly than the detection voltage. The controller () stops an operation of the voltage converter () when the detection voltage is determined to be the first reference voltage or higher through the determination unit ().

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Nara, Japan

Masato Himeda